It is important to be able to accurately and reliably measure the concentration of sulfur in liquids, as various chemical reactions may take place that would release sulfur compounds into the atmosphere or onto physical structures around the sulfur-containing liquid. For example, the combustion of diesel fuel typically generates sulfur oxides (SO2, SO3) and sulfuric acid (condensate H2SO4), both of which are components of acid rain. Further, these sulfur compounds have been linked to catalyst poisoning in diesel particulate filters (DPFs) and sulfuric acid condensation and corrosion of engine components, such as the cooler and piston ring liner components. Such phenomena are found when using both high sulfur (>350 ppm) and low sulfur (10-350 ppm) fuels.
For various reasons, including the sensitivity of aftertreatment components to sulfur compounds, many modern diesel engines are now being designed to use Ultra Low Sulfur Diesel fuel (<15 ppm S). Accordingly, the sulfur level of the fuel source is of utmost importance for optimum machine performance. While sulfur detection in liquids at levels below 15 ppm is attainable in a laboratory or other test setting, such detection is not feasible in the field with an accurate, portable, reliable, quick, and inexpensive sensor. Examples of known means of detecting sulfur at ultra-low levels include Flame Photometry Detection (FPD) and Inductively Coupled Plasma (ICP) devices, but both are more appropriately used in the laboratory setting because of their size and duration of test cycles. Accordingly, a desire for a fast and inexpensive detection of sulfur level in diesel fuels, or possibly an on-board diagnostic tool for determining the same, persists.